[FFmpeg-user] lenscorrection and vignette filters

[Moritz Barsnick]

On Tue, Feb 23, 2016 at 10:00:47 +0100, Michael Koch wrote:
> The remarks "0.5 means no correction" in the documentation are wrong. 
> This can easily be tested:

I know nothing about lens correction formulas, I trust you on this. :-)

> But unfortunately this isn't the only error in the documentation. I 
> haven't yet found out which formula is actually used in the 
> lenscorrection filter, but one thing is absolutely sure: It's not the 
> formula from the documentation.

I can't help you much, but you are free to look at the source code, and
see whether you can see the formula from it:

https://github.com/FFmpeg/FFmpeg/blob/master/libavfilter/vf_lenscorrection.c

I think filter_frame() calls filter_slice(), but don't quote me on
that.

Cheers,
Moritz